Evolutionary dynamics in complex phenotype spaces

点击翻译按钮获取中文摘要

40 years ago, the realization that ecological dynamics can be very complicated, and indeed chaotic, has revolutionized ecology. In contrast, in evolutionary biology the prevalent perspective still is of evolution as an equilibrium process, converging towards optimally adapted phenotypes. This perspective is correct for simple scenarios, when frequency-independent selection acts on simple phenotypes. In most organisms, many phenotypic properties combine in complicated ways to determine ecological interactions, and hence frequency-dependent selection. Therefore, it is natural to consider evolution due to frequency-dependent selection acting simultaneously on many different phenotypes. For example, diversity is more likely to evolve when phenotypes are multi-dimensional. In general, however, very little is known about the theory of evolutionary dynamics due to frequency-dependent selection in complex phenotype spaces. In particular, it is not known how often oscillatory and chaotic evolutionary dynamics are expected to occur. My research aims to address these fundamental questions. I use mathematical models for evolution due to competition, predation and mutualism to classify the different types of evolutionary dynamics occurring in multi-dimensional phenotype spaces, and to assess how often oscillatory and chaotic dynamics occur in such models. Also, I will use whole-genome sequencing of the fossil (frozen) record of microbial populations evolving in nutritional environments of varying complexity to test the effect of phenotypic complexity on evolutionary dynamics. This will show empirically whether in more complex environments, diversification becomes more likely, and evolutionary dynamics exhibit larger fluctuations and become less predictable. Finally, I will use mathematical models to investigate the effect of phenotypic complexity on another fundamental evolutionary problem: the evolution of cooperation. Taken together, the proposed research has the potential to alter our view of general evolutionary processes. If complex dynamics is common in high-dimensional phenotype spaces, then our view of evolution as an equilibrium process must be fundamentally revised.